Time Machine’s Use of Two Backup Drives?

[jaybar]

Hi

I am running Time Machine and CCC as backup options.

Time Machine allows one to use two backup drives. It alternates between them. Are you using TM in this way and if so, do you feel there is a significant advantage? As I said, I am also using CCC, if that has a bearing on the issue. Thanks.

 

[0128672]

I use Time Machine with two external drives connected most of the time. Sometimes I'll disconnect the older drive and only connect it every few days thinking it might help its longevity, but I don't know if that's true.

 

[jaybar]

Thanks

Time Machine has been pretty good about setting up my iMacs.

I use Time Machine with two external drives connected most of the time. Sometimes I'll disconnect the older drive and only connect it every few days thinking it might help its longevity, but I don't know if that's true.

 

[mj_]

Unless your CCC backup is on a third disk running two Time Machine and one CCC backup won't be any safer or better than running one Time Machine and one CCC backup.

The question is: what is it that you're trying to achieve or protect yourself from? How do you think you will benefit from two independend Time Machine backups?

 

[jaybar]

Unless your CCC backup is on a third disk running two Time Machine and one CCC backup won't be any safer or better than running one Time Machine and one CCC backup.

The question is: what is it that you're trying to achieve or protect yourself from? How do you think you will benefit from two independend Time Machine backups?

CCC is on a third external SSD. The reason I was thinking about two TM drives was the slight possibility of drive failure or the TM backup becoming corrupted. I could easily exist with one TM backup.

 

[hfg]

I have been running my iMac this way for over a year ... I have 2 external 3.5" hard disks in a small enclosure on my desk. One is for CCC backup automatically once a day. The other is for normal TimeMachine backups and alternates hourly backups with a RAID5 system in the basement over the network. So far ... no problems!

 

[mj_]

CCC is on a third external SSD. The reason I was thinking about two TM drives was the slight possibility of drive failure or the TM backup becoming corrupted. I could easily exist with one TM backup.

If you're afraid of both your backup disks failing then adding a third can help you sleep better at night. Realistically speaking the chances of that happening are slim to null. It's more like for all your backup media to get destroyed in a house fire, a natural disaster, or to get stolen. In that case a secondary Time Machine disk would only make sense if you kept one of the two off-premise at all times.

In your case, and since you seem to be somewhat concerned about the reliability of your backup drives, you may want to consider cloud storage as tertiary backup medium.

 

[NoBoMac]

Will echo @WildSky, in that I too use two TM drives. I swap them every two weeks.

And will echo @mj_ re: need to have something "off-site".

Now some heresy: I've stopped doing clones. Thinking being, what with almost everything in a Mac is soldered these days, if you have a dead machine, probably won't boot anyway off a clone, so why bother. I've got multiple off-sites, Time Machines, and Photos library has been on an external SSD for a while now, not a lot of programs to restore, recovery to a new machine will not be a big deal without a clone. Imo, my $0.02.

(not saying clones are a bad thing, just seems over kill for me, my workflow)

 

[jaybar]

Will echo @WildSky, in that I too use two TM drives. I swap them every two weeks.

And will echo @mj_ re: need to have something "off-site".

Now some heresy: I've stopped doing clones. Thinking being, what with almost everything in a Mac is soldered these days, if you have a dead machine, probably won't boot anyway off a clone, so why bother. I've got multiple off-sites, Time Machines, and Photos library has been on an external SSD for a while now, not a lot of programs to restore, recovery to a new machine will not be a big deal without a clone. Imo, my $0.02.

(not saying clones are a bad thing, just seems over kill for me, my workflow)

I am beginning to feel similar about clones. Particularly since I have a new M1 iMac. Thanks.

 

[glenthompson]

I don’t do a bootable clone but I continue to use CCC to make a clone of my data. Still use Time Machine for one backup but the remainder are CCC or BackBlaze.

 

[jz0309]

Backing up my data (1 internal and 1 external SSD) via CCC onto 2 SSDs.
Cloning is not really working anymore with Big Sur - detail are in the CCC thread under Big Sur

Also planning to do TM onto an external HDD, just seems that 2 HDDs failed almost simultaneously (I will create a new post for that experience of mine), need to get a new external HDD asap.

 

[tri-x]

Also planning to do TM onto an external HDD, just seems that 2 HDDs failed almost simultaneously (I will create a new post for that experience of mine), need to get a new external HDD asap.

Wow! Two drives failing almost simultaneously. That's very unlucky! Were the same brand/type of drive? Bought at the same time?

 

[jz0309]

Wow! Two drives failing almost simultaneously. That's very unlucky! Were the same brand/type of drive? Bought at the same time?

see my post:

2 external HDDs failing AFTER Big Sur upgrade?? or?

2 WD easystore USB 3 hard drives: 8TB now almost exactly 4 years old, used for TM backup - never seen any issue/error messages 4TB ~ 3month younger than above, used it for iTunes and some duplicate files, other than accessing music/movies no other day-to-day files About 6 weeks ago II erased the...

forums.macrumors.com

 

[wilberforce]

Time Machine verifies the backups from time to time, and will occasionally give the message "Time Machine completed a verification of your backups.... To improve reliability, Time Machine must create a new backup for you."
What this means is that you lose the prior backup, and it restarts a new backup!
Having two alternating backup drives mitigates this loss of backup